1. Field of Use
This invention relates to a one-piece molded plastic fastener for mounting a first panel on a support member, such as another panel, so that the first panel can be detached and reattached.
The fastener comprises a pin attachable to the first panel, a hollow grommet attachable to an installation hole in the support member, a frangible web initially interconnecting the pin and grommet but enabling the pin to be forcefully inserted into and subsequently withdrawn from the hollow grommet, and sealing means for the installation hole in the support member.
2. Description of the Prior Art
Various types of prior art fasteners are known or available for detachably mounting a first panel on a support member, such as another panel. Some of these fasteners are adapted to detachably mount a decorative and/or protective liner panel on the inside of an enclosed space in a piece of equipment such as an automobile or domestic appliance. In automobiles the passenger compartment and trunk use such liners. Domestic appliances, such as refrigerators or dishwashers, also use them. The liner panel needs to be removable and replaceable to enable servicing or replacement of components therebehind. Usually, a plurality of fasteners are used to secure each liner panel to the inside of a support member which, for example, typically takes the form of a rigid stamped sheet metal support panel forming part of the automobile or appliance structure. The support panel also provides mechanical support for other components in the structure. Some fasteners are one-piece or two-piece metal or plastic devices which are screwed or press-fitted in registering attachment holes in the liner and the support panel. Some attachment holes in the support panel are in locations where there is a risk of liquids leaking therethrough from the outside of the support panel and causing damage to, deterioration of or unsightliness in the associated liner or other components. In automobiles the liquid might be rain water, water splashed from the road, wash water, gasoline, oil or other liquid automotive products. Some fasteners are provided with separate or integral sealing washers or sealing devices to prevent leakage.
U.S. Pat. No. 4,393,551 entitled "Rotatably Engaging Head For Fasteners", issued July 19, 1983 to Wollar and Schwind, and assigned to the same assignee as the present application, discloses a one-piece, injection-molded, self-sealing plastic fastener which is especially well-suited for the aforementioned purposes. This fastener has a special head which is twistably insertable manually into a pre-formed attachment hole in a liner panel and has an integral shank, with flexible resilient locking projections thereon, which is axially insertable into a registering pre-formed attachment hole in a support panel. To mount the liner panel with a plurality of such fasteners already attached thereto, the liner panel is placed adjacent the support panel in confronting relationship so that each fastener shank is axially aligned with the appropriate attachment hole in the support panel. Then, the liner panel is pressed-toward the support panel to cause the fastener shanks to enter the attachment holes therein, whereupon the flexible locking projections engage the edges of the attachment holes and secure the liner panel to the support panel. The flexible locking projections enable the liner panel to be detached merely by pulling it away from the support panel, carrying the fasteners with it, and also enable the liner panel to be reinstalled, as aforedescribed. This fastener comprises an annular flexible resilient sealing flange on its shank between the head and the locking projections, which flange engages the inside surface of the support member and seals the attachment hole therein against liquid leakage when the shank is fully inserted thereinto and the liner panel is properly mounted on the support panel.
The fastener of U.S. Pat. No. 4,393,551 is satisfactory for its intended purpose, but there is a possibility that, if it is not properly installed, the sealing flange will not completely seal the attachment hole and a risk of leakage will exist. Furthermore, because the resilient flexible plastic locking projections directly slide across and engage sharp edges when inserted in an attachment hole in a support panel made of sheet metal, improper installation of the fastener or repeated insertion and withdrawal of the shank (occasioned by frequent detachment and reattachment of the liner panel) can damage the projections and render the fastener unfit to firmly secure the liner panel in place or unfit to enable an effective seal when mounted on the support panel. Therefore, there is a need for an improved fastener for this purpose.